"This is an everyday supercar you can effectively drive every day," he says as various versions of the SLS, now called the SLS GT with a more powerful engine, skid around a raceway behind him in the California desert.

Mercedes isn't the only carmaker trying to tackle the practicality issue head-on. They are seeking to change attitudes that their sports cars are exotic machines only for weekend fun -- second or third "garage queens" that became unjustifiable to own because they'll never be driven to work.

"Frankly, if you are paying $80,000 or $100,000 for a car, you need some level of practicality to justify it," says Ian Beavis, executive vice president for Nielsen Global Automotive and a former marketing chief for Kia and Mitsubishi.

Other examples of touting practicality alongside performance:

* Porsche. The German automaker created a "Porsche Everyday" ad campaign for its 911 sports cars two years ago. One ad, for instance, showed a mum dropping off a child in a bright yellow 911, flashing the words "school bus". The companion website is headlined, "Engineered for usability. Every day". Sales of 911s rose by 64.8 per cent in the US last year, Autodata reports.

* McLaren Automotive. In introducing its MP4-12C supercar last year, US sales chief Anthony Joseph pitched the 330km/h speed demon as the "ultimate sports car" that's "a car you can drive every day". Some owners drive the two-seater to work. "It's a car with a dual personality," Joseph says.

* Ferrari. For the FF, its first four-seat sports car, Ferrari stresses its "everyday comfort and versatility" on its website. The FF has a top speed of 335km/h from its 485kW engine.

Beavis says, however, that despite the marketing spin, thinking of practicality for such cars amounts to a sort of "post rationalization".

That's because there is no getting around the primary reason for buying one: speed. Practicality will always be "oh, by the way".